Miss Welch, originally from Crewe, but who now lives in Plymouth, said she was shocked when she first read what was written.

"When he handed it to me he said it had fallen out of my bag, so I just said thank you and took it from him," she said

"When I looked at it and saw what was written I was so shocked.

"I feel really overwhelmed by it all, it was just so lovely to get it.

"I was so shocked at the fact he had put the money in it, I couldn't quite believe it.

"I've put the money in a savings account for Rylan now, I thought that was the best place for it.

"Money is quite short for people nowadays so for someone to give me that was amazing, and I want to put it to good use."

Miss Welch has now launched an internet search in a hope to trace the gentleman, who she describes as in his early 50s.

She added: "When he described himself at the end of the note as the table across from me I was trying to rack my brains to see if I could remember him but there were that many faces on the train they all blur into one.

"I really, really wish I could remember him but I just can't, I think he was around his early 50s, but I don't want to offend him if I really got it wrong.

"I'm trying to hard to recall the people and put things together but because he was getting off the train it all felt so rushed.

"I have no clue so I'm hoping people might be able to help me out.

"I wish I had looked at him in more detail, I really want to thank him personally.

Miss Welch was on a First Great Western train from Birmingham to Plymouth on Thursday when a man handed her the note as he got off in Bristol at around 7 or 8pm.

The mother-of-one was attempting to entertain Rylan during the busy service and said she was simply playing with him as he ate his dinner.

"All I was doing was entertaining him really," Miss Welch said.

"He was eating his dinner, I had made him a packed lunch, and we were laughing at the fact he kept calling his grapes strawberries.

"He was just being a happy, laughing little boy. We were playing together and I was trying to keep him occupied.

"He normally gets quite rowdy and bored on long trains so I was doing my best to entertain him as much as I could."

After his dinner Rylan fell asleep, sprawled across his mother and another seat.

When another passenger came to sit down Miss Welch quickly moved Rylan on to her lap, insisting the man took the seat rather than stand.

Shortly after, the unknown admirer handed Sammie the note before disappearing into the rush to get off the train.

Miss Welch said: "Both me and the man next to me were a bit confused at first.

"Once I'd taken it we realised it couldn't have come out of my bag because I was sat next to the window.